The invention relates to an outside rear view mirror.
Such an outside rear view mirror is known from DE-OS 198 33 672 A1. In the known outside rear view mirror, both a power-driven displacement and a manual folding of the mirror are possible. During the manual folding in and against the direction of travel, a toothed gear disengages from the holding means on the mirror foot, whereby the mirror head is shifted relative to the mirror foot along the swivel axis. In the disengaged state, there is no longer a positive engagement connection between the toothed gear and the mirror foot, but instead a frictional engagement, which is sufficient to swivel the mirror head relative to the mirror foot by the power drive. If the outside rear view mirror is to be moved back into its starting position by the power drive, the holding means must be synchronized. This can only happen when the mirror head meets an obstacle. The folding path limiter represents this obstacle. The mirror head must therefore first be moved into the park position, where the mirror meets the folding path limiter. Only in this stop position can the toothed gear be twisted relative to the mirror foot and thus be synchronized. Only then can the mirror head be swivelled back into the driving position. This procedure takes a relatively long time, and may possibly be misunderstood by the user.
Thus the object of the present invention is to design an outside rear view mirror so that a rapid synchronization of the holding means is possible when the mirror is folded manually, without unnecessary swivel movements.
This object is achieved, according to the invention, when the mirror head is folded manually, the drive is actuated in order to swivel the mirror head back into the driving position. An obstacle has been created by the stopper and counter-stopper, which obstacle acts in the driving position and not only at the folding path limiter. When the drive is actuated, the mirror head stops its swivel movement at this obstacle, whereby the holding means are again synchronized until they again engage. It is therefore only necessary to displace the mirror electrically from the folded position into the driving position. Because of the short displacement paths, the entire procedure can be accomplished relatively quickly. Since the stops in the driving position only act in a raised position, they do not hinder the use of the mirror or its folding function.
The simplest construction is achieved by arranging the holding means in the mirror foot and on a toothed gear associated with the drive. In normal operation, the toothed gear is then a quasi component of the mirror foot.
It has proved good to construct the holding means in the form of holding cams and holding recesses whose flanks are inclined. These are simple to manufacture and the force required to disengage them can be defined by the selection of the angle of inclination.
A further influence on the force required to disengage them is exerted by a spring with which the toothed gear is held on the mirror foot. The toothed gear is preferably arranged thereby between the mirror foot and mirror head, co-axially with the swivel axis, whereby it meshes with the gear of the drive.
In the disengaged state, the toothed gear and the mirror head are raised relative to the mirror foot, by which means the is disengaged state can be recognized simply electronically via a touch contact. Furthermore this makes it possible to construct the stopper in a simple manner so that it can act only in the manually folded state.
The stopper and the counter-stopper can be arranged opposite one another in the driving position. As a result, the disengagement procedure is not hindered as a rule, in particular because the holding means on the toothed gear and the mirror foot are not constructed in the form of steps as a rule, so that a swivel movement is also performed during the disengagement procedure.
It is preferred to construct the stoppers and counter-stoppers with inclined stopper faces so that the engagement procedure can be performed in a sliding manner. This is further promoted if the angle of inclination of the stopper faces corresponds to the angles of inclination of the holding recesses and holding cams.
It is possible for the holding means also to disengage during a manual folding movement against the direction of travel; it is then important that the stoppers and counter-stoppers do not stand in the way of this disengaging movement, in order to prevent damage to the drive or the mirror. It is therefore provided that in the engaged state of the holding means, the smallest distance between the stopper and the counter-stopper in the axial direction is less than the maximum lift that the mirror head performs versus the mirror foot as it disengages. It is further provided that in the engaged state of the holding means, the smallest distance between the stopper and the counter-stopper in the axial direction is greater than the width of the stopper or the width of the counter-stopper respectively in the swivel direction on the side opposite to the counter-stopper or the stopper, respectively.
In order to prevent damage to the drive or the mirror by the stoppers and counter-stoppers, the stoppers and/or counter-stoppers can also be constructed with predetermined breaking points or as flexible components. There is then only a danger of damage if the mirror is in an intermediate position between the driving and park position and an external force acts on the mirror head.
In order to achieve a more uniform distribution of the occurring forces, several stoppers are provided, preferably two.
A very simple construction of the stoppers or counter-stoppers is achieved in that the counter-stopper on the mirror foot is formed by a washer holding down the pressure spring, which washer is fixed to a link pipe forming part of the swivel joint so that it is unable to twist. It is particularly suitable to construct the washer in the shape of a pot, whereby the counter-stoppers are arranged at the edge of the pot.
Another possible method for preventing damage to the drive or the mirror during manual folding consists in that a friction coupling is arranged between the mirror foot and the toothed gear, whereby the friction coupling only becomes active when the mirror is being folded manually against the direction of travel. In the direction of travel, stops are provided between the mirror head and the mirror foot that allow the drive to twist in a manner that is free from play, in order to minimize vibrations of the mirror. These stops are inclined towards the swivel direction, in order to enable an xe2x80x9cover-engagementxe2x80x9d.
It is preferred that the toothed gear be connected flat via at least one friction face to a holding ring provided with the holding means, essentially annular, and arranged co-axially with the swivel axis, whereby the holding ring is arranged between the toothed gear and the mirror foot and the holding means on the holding ring and the mirror foot are shaped so that the disengaging moment is considerably smaller when an external force (FIF) acts in the direction of travel than when an external force (FGF) acts against the direction of travel, and the friction moment between the toothed gear and the holding ring is greater than the disengaging moment between the holding ring and the mirror foot when an external force (FIF) acts in the direction of travel, but smaller than the disengaging moment between the holding ring and the mirror foot when an external force (FGF) acts against the direction of travel. Due to the high friction force between the toothed gear and the holding ring, the outside rear view mirror with a power drive behaves like the previously known outside rear view mirror. When an external force (FIF) acts on the mirror head in the direction of travel, the holding means of the holding ring connected by friction to the toothed gear disengage from the holding means of the mirror foot, because the holding means are shaped so that they can disengage in this direction, whereby the frictional force is greater than the disengaging force in the direction of travel. During disengagement from the holding means, the driving path limiter between the mirror head and mirror foot, which can not be overcome by the power drive, is also overcome. The folded mirror head can then be brought back into the driving position by the power drive.
When an external force (FGF) acts on the mirror head against the direction of travel, the holding ring connected to the toothed gear by friction does not disengage from the holding means of the mirror foot, because the holding means are shaped so that they jam in this direction. For this reason the frictional force between the toothed gear and the holding ring can be overcome by the external force, until the driving or folding path limiter is reached. Then the mirror can be brought back into the driving position by the power drive, without the necessity for initiating a synchronization procedure between the holding means on the holding ring and the holding means on the mirror foot, since the co-ordination between the holding ring and the mirror foot is maintained, even with this forced procedure. This reduces the time required for the return procedure and also simplifies the optionally present control for this.
In a preferred form of this embodiment, the holding means are constructed in the form of holding cams and holding recesses whose flanks are inclined differently. Because of the different inclination of the flanks, disengagement is only possible in one direction. It is unimportant thereby whether the holding recesses or the holding cams are arranged in the holding ring or in the mirror foot.
In order to enable a power-driven return of the mirror head into the driving position in all situations, it is provided that the mirror head can take up position at several height levels relative to the mirror foot, whereby a frictional connection between the toothed gear and the holding ring exists at all height levels and in all angles of rotation positions of the mirror head, which frictional connection is maintained by means of the pressure spring. The positive engagement connection between the holding ring and the toothed gear would be broken if parts of the mirror head were to sit on parts of the mirror foot in the disengaged state.
In order to prevent this, in this position, at least a small gap must be present between the mirror head and the mirror foot in the swivel axis direction.
In order to enable the mirror to be folded in the direction of travel by means of an external force, the driving path limiter between the mirror head and the mirror foot must be overcome and the mirror head must be able to take up a position relative to the mirror foot at two height levels (H, L), a low (L) and a middle (H) level. In order to reach the middle height level (H) from the low level (L), in a particularly advantageous form of this embodiment of the invention, a third height level (Z) must be overcome. It is not intended thereby that this third height level (Z) should be occupied for any length of time; rather, under the influence of an external force it is to be attained only briefly and is left again immediately. The third height level (Z) should not be attainable by the power drive either from the height level (L) or from the height level (H). This rules out the possibility that during incorrect operation of the outside rear view mirror, the holding ring could engage in the holding means of the mirror foot in a mirror position that is folded forwards in the direction of travel. This incorrect operation occurs when the folded mirror is moved by the power drive further in the direction of travel until the folding path limiter is reached. Then the toothed gear would move as though it was trying to reach the third height level (Z); since this is not possible by the power drive, the drive jams at this point. If the third height level (Z) were not present, the holding ring would engage in the holding means of the mirror foot and the mirror head would lie directly on the mirror foot under the force of the pressure spring. This would break the frictional connection between the toothed gear and the holding ring, and no further power-driven actuation would be possible.
In order to exclude the risk of the third height level (Z) being occupied for any length of time, projecting formations are provided immediately adjacent to the holding recesses. In this position the maximum moment caused by the action of an external force and acting on the mirror head is to be expected. The moment required for disengagement is so high that over a short path or in a short time, it cannot be degraded sufficiently for the mirror head to remain at the third height level (Z) for any length of time.
It is advisable for the low height level (L) to be possible only between the driving position (F) and the park position (P), which ensures that no situation is possible in which a mirror folded forwards in the direction of travel can end up in a position where it can no longer be returned by the power drive.
It is also provided that the second height level (H) is possible only in the mirror positions (K) folded forwards in the direction of travel. Thus wear of the holding means on the mirror foot is only possible during the fairly rare folding in the direction of travel by means of an external force (FIF). In is addition, the driving path limiter hereby absorbs part of the occurring forces.
To ensure that the third height level (Z) is attained only briefly, it is necessary that the third height level (Z) be possible only between the driving position (F) and a mirror position (K) folded forwards in the direction of travel. In this position, as mentioned above, the moment required to be able to fold the mirror at all is greatest; once this moment is applied, it is scarcely possible to reduce it again sufficiently and rapidly enough for the third height level (Z) to be maintained. It is also advisable to design the projecting formation on the holding ring or on the mirror foot so that stable positioning on the third height level is impossible. If the third level were able to be attained for any length of time, it is indeed true that a power-driven displacement would continue to be possible, but an incorrect operation, as mentioned above, could lead to incorrect functioning.
It is preferable for the transition between the middle height level (H) and the third height level (Z) to be designed as a stop, whereby the stop is designed as an inclined face relative to the swivel plane. This enables the mirror to be brought back into the driving position manually also, overcoming the third height level (Z). Since the third height level (Z) is not intended to be attainable by the power drive, however, the inclination of the face of the stop is designed accordingly.
According to a preferred development of the invention, the friction area between the toothed gear and the holding ring is conical. The frictional force between the toothed gear and the holding ring is sharply increased by the cone. The frictional force can be adapted to the requirements by the selection of the angle of inclination.